Samsung ue55nu7021k Boot cycle

[Yoda79]

Hi, wondering if anyone can help with a tv which seems to turn on but turn off soon after and continue to do this cycle over and over again.

It turns on, no sound and then turns off and starts the whole cycle again. I've opened up the back and can see the backlights turning on. However when I disconnect the two straps connecting the left hard board (as you look on the back of the TV), the boot cycle stops and it does turn on and I can hear the boot up sound, however no video?

Any thoughts, any help would be greatly appreciated.

[Davi.p]

usually there is a shorted glass panel, in some lucky situation only a bad cap or diode on the bevel boards..

[EazyBone]

Yes, likely TV panel is bad, or as Davi said. Search for, fixing TV with tape, and watch the video. Try it see what happens.

If you are more advanced check the buffer boards for shorts. If there are some report back here

[Davi.p]

sorry,.border boards i mean

[Yoda79]

Thanks guys, just had a look at a video on fixing with tape. Where would you apply the tape, to the part of the ribbon which connects with the main board or the part which joins what I believe is called the TCON, although I don't seem to have an obvious one?

I have 2 ribbons, and disconnected each in turn and with both the tv doesn't constantly reboot and stays on, as I can see the back lights staying on. With both ribbons, when I disconnect one, the sound comes but not when both ribbons are connected. I had assumed that by connecting a good ribbon, some the picture may come on but not the case, what would that suggest?


I'm not advanced but can I ask how you check the buffer boards for shorts?

Thanking you all again for your help.

[EazyBone]

There is no stand alone TCON here. You can tape any side you want. Main board or buffer board side. This is basically just a diagnosis test that may help see if it's actually the panel. It's not 100 percent but works well. Pick a side, cover like 8-16 pins, try different ones. And generally try the edges with the tape, it's usually not in the middle pins of the ribbon.

Also the buffer boards are under the speakers and metal cover. For this you need multi meter.

Try the tape, it's rare that buffer boards have short but not unusual

[Davi.p]

On border boards there are some bigger caps,test them across for short

[Yoda79]

There is no stand alone TCON here. You can tape any side you want. Main board or buffer board side. This is basically just a diagnosis test that may help see if it's actually the panel. It's not 100 percent but works well. Pick a side, cover like 8-16 pins, try different ones. And generally try the edges with the tape, it's usually not in the middle pins of the ribbon.

Also the buffer boards are under the speakers and metal cover. For this you need multi meter.

Try the tape, it's rare that buffer boards have short but not unusual

Is it strange that I get the same result when I take each ribbon out, in that in either case the power is steady (doesn't reboot) and I hear sound? I had assumed one would deliver steady power and the other would cause it to just reboot highlighting that the ribbon with the fault? Which then allows me to start to test that particular ribbon?

[Yoda79]

On border boards there are some bigger caps,test them across for short

Sorry can I ask what you mean by bigger caps? Also, I have a multimeter but how would I test for shorts? Not testing the buffer boards yet as will check the ribbon and tape off as suggested here, but curious on this now.

[Davi.p]

the border board consists of different sizes of caps (capacitors), test in ohm for almost zero across the big ones

[Yoda79]

the border board consists of different sizes of caps (capacitors), test in ohm for almost zero across the big ones

Ok great. So to get to the border board, do I just remove the speaker and then remove the cover plate?

[Davi.p]

of.course

[EazyBone]

Is it strange that I get the same result when I take each ribbon out, in that in either case the power is steady (doesn't reboot) and I hear sound? I had assumed one would deliver steady power and the other would cause it to just reboot highlighting that the ribbon with the fault? Which then allows me to start to test that particular ribbon?

I believe there is a spot to jumper/solder on the board you have to do before you can remove just one side of cable and get half a picture. So no not unusual for this TV. Tape in the correct spot should give you a startup. Works for me bout 90 percent of time if I hit the right "spot"